Cables for prospecting, in particular for undersea oil prospecting must withstand ambient pressure, transmit power to control the equipment laid at the bottom and convey to the surface the data which comes from the measuring equipment. Such cables must have high tensile strength and high bursting strength, they must withstand high temperatures and remain insensitive to the action of hydrocarbons which cause many elastomers to swell and which are used to constitute the sheaths of usual cables.
Known prospecting cables of this type include bundles of conductors which are insulated from one another, a flexible casing around the bundles and outer reinforcement formed by two layers of steel wire wound helically in opposite directions. Such cables are incapable of transmitting high-frequency bands and can therefore transmit only a limited amount of data unless they are of large diameter which then entails high manufacturing cost and difficulties in laying.
The present invention aims to remedy the above drawbacks and to produce a cable for oil prospecting which cable simultaneously transmits power and a large quantity of data while it has a relatively small diameter, is not very expensive and is easy to lay.